This invention relates generally to a driving system for an active matrix panel for a liquid crystal display device and more particularly to an active matrix panel utilizing thin film transistors. Heretofore, liquid crystal display has been used for small sized display devices such as a timepiece, and the like. However, today it is necessary to use aliquid crystal display for a large-sized display device such as a computer terminal or a pocket television, and the like, where the liquid crystal display is necessary to have a large area. However, in a conventional method, a generalized AC amplitude selected multiplexing method is limited to a driving duty cycle of 1/30 to 1/50 and it is difficult to realize a large-size display having a duty cycle, for example, of 1/500. In order to improve the driving duty cycle, it has been suggested to use a transistor such as a thin film transistor (TFT) or an active element such as metal-insulator-metal (MIM) element for writing and holding of data for each picture element. Strictly speaking, a MIM is not active but in this invention, it can be defined as an active element. There are other difficulties in adapting liquid crystals to a large type display such as for television signals. When a twisted nematic positive type liquid crystal is used in the matrix, the level of whiteness and blackness of the video image is inverted when the video signals, intended for cathode ray tubes, are used unmodified. Additionally, a video signal intended for a cathode ray tube, when applied to a liquid crystal of the twisted nematic type provides insufficient contrast in the range of whiteness. Additionally, thin film transistors suffer from much higher levels of backleakage such that the picture quality deteriorates between picture element selection in each picture field as a result of this leakage.
What is needed is an active matrix panel using liquid crystals which is capable of providing a large display with good quality suitable, for example, for television.